Apparatuses such as communication devices that accommodate lines are not only installed indoors but are also installed outdoors as required.
Normally, the outdoor temperature varies more widely than the indoor temperature. Accordingly, when the outdoor temperature is high, the interior temperature of an apparatus installed outdoors may increase unnecessarily due to the high level of the outdoor temperature (exterior temperature of the apparatus). In such a case, it is necessary to protect internal devices against the high temperature situation.
In general, a radiator called a “heat sink” that decreases the temperature through thermal radiation is often used to decrease the temperature of a device in operation.
There is such a technique in which the temperature inside an apparatus is monitored so as to shut off the power supply to the whole apparatus when the temperature inside the apparatus becomes higher than the normal temperature level (see Patent Document 1 for example).